The present invention relates generally to the field of threaded fasteners, and more particularly to a threaded fastener, such as a threaded nut or bolt, joined in an assembly with a stemmed washer. The invention also relates to a manner for retaining a stemmed washer in an assembly with a threaded fastener, and to a method for making the assembly.
A variety of applications are known for threaded fasteners used with standoffs. In a number of applications wherein one or more compressible materials are to be secured, for example, a standoff is commonly inserted into an aperture in the compressible material, and threaded or other fasteners are placed through the standoff for securing the compressible material in a desired position. Compressible materials on which standoffs are commonly used include various plastics, rubbers, foam materials, and so forth, but may also include expanded metals, cellulosic products, and so forth. Moreover, standoffs are also commonly used in applications wherein penetration of one or more fasteners is to be limited, although the material being fastened in place is not necessarily particularly compressible, such as in fragile or brittle materials.
Where applications call for the use of mechanical standoffs, prior art arrangements have typically relied upon separate components which are brought together in place to permit securing without crushing compressible materials, or while maintaining a desired distance between mechanical components, typically a screw or bolt and a nut. Thus, in a traditional assembly, a standoff is placed in the receiving aperture, a screw or bolt is passed through the aperture and standoff, and a traditional washer and nut are secured on the opposite side. While such arrangements provide generally adequate resistance to crushing and maintain desired mechanical distances between the joined fasteners, they require several separate parts and can entail considerable assembly time for insertion of the standoff, and assembly of the fasteners. Moreover, the various separate parts must be individually manufactured, shipped, stored and brought together in the final assembly.
There is a need, therefore, for an improved arrangement for securing fasteners to one another in applications requiring standoffs. There is a particular need for a technique that would facilitate assembly, while providing a high degree of resistance to crushing, and which would maintain desired distance between elements of the threaded assembly.